Rheumatic diseases affect a significant proportion of the population, crippling many people and having only a palliative treatment at best. Diagnosis of rheumatic diseases is difficult and uncertain, and many patients escape classification until the disease has progressed to a stage where serious damage is evident. The classification of the different rheumatic diseases, including rheumatoid arthritis, is based on both clinical and laboratory data, and the same criteria are used to determine the efficiency of any selected treatment. In all of the rheumatic diseases, the common denominator is an abnormal function of the immune system. This abnormal function is suggested by the appearance of antibodies against a patient's own structures and also by the beneficial effect of immunosuppressive or cytotoxic drugs which destroy cells involved in the immune mechanisms.
It has been shown that in some of these diseases the B-cells that produce antibodies are overactive, and produce antibodies against a variety of antigens, including some to which they may not have been previously exposed. Another relatively common feature is the increase in the serum immunoglobulin with polyclonal character. From such observations, it has been ascertained that B-cells programmed to produce antibodies against self antigens are present in normal individuals. It has likewise been suggested that polyclonal B-cell activation may be the cause of some autoimmune diseases.
Despite such studies of rheumatic diseases, there remains a critical need for a diagnostic technique capable of providing, with suitable certainty, an early diagnosis of the incidence of such diseases. This is especially true of the crippling diseases, such as, particularly, rheumatoid arthritis.